File:GISP2 Ice Core.jpg

From Global Warming Art


An example of temperature, carbon dioxide, and dust data retreived from analyzing ice cores such as this one.

This photograph shows a 1 meter section of the GISP2 ice core from a depth of 1837 meters in the Greenland Ice Sheet. Annual layers are clearly visible in this image. The appearance of layers results from differences in the size of snow crystals deposited in winter versus summer and resulting variations in the abundance and size of air bubbles trapped in the ice. Counting such layers has been used (in combination with other techniques) to reliably determine the age of the ice (Meese et al. 1997). This ice was formed ~16250 years ago during the final stages of the last ice age and approximately 38 years are represented here. By analyzing the ice and the gases trapped within, scientists are able learn about past climate conditions.


This image was produced at the National Ice Core Laboratory by employees of the USGS with funding from the NSF, and consequently is in the public domain.

It was kindly provided by Eric Cravens, Assistant Curator, National Ice Core Laboratory.

This image is a work of a United States Geological Survey employee, taken or made during the course of the person's official duties. As a work of the United States Government, the image is in the public domain. For more information, see the USGS copyright policy.


  • [abstract] [DOI] Meese, D. A., A. J. Gow, R. B. Alley, G. A. Zielinski, P. M. Grootes, M. Ram, K. C. Taylor, P. A. Mayewski, and J. F. Bolzan (1997). "The Greenland Ice Sheet Project 2 depth-age scale: Methods and results". J. Geophys. Res. 102 (C12): 26,411–26,424. 

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